Known to family and friends as "Judson", he was the son of James Humphreys and Olive E. (Conser) Humphreys. He is buried alongside his wife, Jeanetta Mae (Raum) Humphreys. The other side of the gravestone at Woodsdale Cemetery marks the burial of his parents (James and Olive). Though leading a scientifically famous life, he and "Jean" came back to his childhood homeland to be laid to rest, as family was very important to them. They attended the annual Humphrey Reunion in New Garden, Ohio as often as possible from its beginnings in 1921, and Judson often spoke to the group with his annual talks that were both "worldly" and "down home" in nature at the same time.

Curtis Judson Humphreys, as printed in "Physics Today", August 1987, Pages 84-86:

"Curtis Judson Humphreys died 22 November 1986, less than three months before his 89th birthday, at his home in Delaware, Ohio.

Humphreys was born in Columbiana County, Ohio, on 17 February 1898. He obtained an AB degree at Ohio Wesleyan in 1918, an MS at the University of Kentucky in 1921 and a PhD in physics at the University of Michigan in 1928.

His dissertation concerned the observation and analysis of the highly ionized spectra of arsenic and selenium and was done under Ralph A. Sawyer. While at Michigan Humphreys worked intimately with Samuel A. Goudsmit, assisting him with the preparation of manuscripts, one of which they published as coauthors. This was a rare opportunity for a young graduate student to have a small part in the development of quantum dynamics.

He then joined the National Bureau of Standards where he spent most of the years between 1928 and 1953. When the Corona Laboratories of NBS were transferred to the Department of Navy in 1953, Humphreys became head of the infrared division at Corona, and in 1957, head of the research department, the post he held until his retirement in 1967. Three months after his retirement he rejoined the laboratory at Corona as a research associate, continuing his basic research until the dissolution of the laboratories in May 1969.

He went immediately to Purdue University as a research associate in the physics department where he continued active work in atomic spectroscopy for another three years with me. Beginning about 1930 Humphreys started making wavelength determinations with the Fabry-Perot interferometer. Results of the first measurements appeared in the Transactions of the International Astronomical Union containing the draft and meeting reports of Commission 14 of that body following the meeting in 1932. For approximately 40 years some contribution to the International System of wavelength standards, originating in Humphreys's program, appeared in the report of the commission following every triennial meeting. Of his earlier work with the NBS group particular mention should be made of the analyses of the spectra of Krypton and xenon and their various ions.

During the World War Humphrey was one of a team of spectroscopists working on the Zeeman-effect experiment and analysis that established that uranium was a member of a second rare earth series and not a homologue of tungsten. An important consequence of this work was the rearrangement of the periodic chart of atoms, which correctly placed Th, Pa, and U along with the transuranic elements on a separate line below elements Ce to Lu rather than as homologues of Hf, Ta, and W.

Humphreys was among the first to recognize that the improved radiometric techniques that had evolved during the war permitted a new assault on the infrared spectrum of hydrogen. Thus it was by a radiometric technique that he was the first to observe and report the sixth series of the emission spectrum of atomic hydrogen of a wavelength of 12.37 micrometers. This series is now called the "Humphreys Series" in physics textbooks. His work in infrared atomic spectroscopy piror to 1954 was recognized in an invitation to give a talk at the Rydberg Centennial Conference on Atomic Spectroscopy held at the University of Lund, Sweden, 1954. He shared this signal honor with William F. Meggers, Niels Bohr, Wolfgang Pauli, A. G. Shenstone, G. Racah and H. Kopfermann. The availability of photoconductive detectors following the end of World War II made possible the extension of high-resolution observations into the infrared region well beyond the limit accessible to photography. His recording of a line in Xe I at 55 772.4 A was the farthest observation in the infrared by this method at that time. Humphreys achieved a significant breakthrough by 1955 with the development of a Fabry-Perot interferometer system for use in the infrared, capable of operating at order numbers in the range of 105. Negative results lay in the development of a mechanism for scanning the interference pattern across a slit by a uniform rotation of the interferometer. Up until this time optical standard wavelengths of eight significant figures were essentially limited to the 0.3-0.9-micron region. However, progress in molecular spectroscopy made for an acute need for wavelength standards in the 2-7-micron region. In 1958, Humphreys and his coworkers were able to report values in this region to eight significant figures—and indeed, some of his values of argon and neon lines were accepted as provisional wavelength standards by Commission 14. These were the first wavelengths of lines beyond the photographic limit ever to be considered in the half century of the Union's existence. Three years later independent, concordant determinations made by entirely different techniques were submitted by E. R. Peck and T. A. Littlefield to satisfy the provisions of the IAU for standard wavelengths, so that they no longer needed to be considered as provisional. In addition to his many scientific achievements, Humphreys was known for his warm and friendly personality, for the many droll stories, always appropriate to the occasion, that he would recall and deliver in his inimitable manner, for his silent step, his ready smile and his inexhaustible vocabulary."

KENNETH L. ANDREW

Purdue University

West Lafayette, Indiana

Curtis Judson Humphreys (17 February 1898 - November 1986) was an American physicist born in Alliance, Ohio, USA. He was chief of the Radiometry Section of the U.S. Navy during the 1940s. He is famous for discovering the Humphreys series of the hydrogen atom.

Biography Humphreys married Jeanette Mae Raum, with whom he had a son Richard.

He was involved in the Spectroscopic Program covering the NBS and U.S. Naval Ordinance Laboratory, Corona, CA, experiences. His inventions significantly advanced the techniques of radiometry and spectrophotometry. He credited the Corona Lab program with the establishment of the atomic wavelength standard in the infrared.

Humphreys attended the Rydberg Centennial Conference on Atomic Spectroscopy in 1954, which at the time was the most distinguished group of spectroscopic and atomic physicists ever assembled, and included the eminent Niels Bohr.

He corresponded with William F. Meggers while in Michigan in 1928.

• Awards and Accomplishments He received the Naval Award for Achievement in Science.
• He was awarded the William F. Meggers Award in 1973.
• He was listed in "World Who's Who in Science" in 1968.

Works Humphreys is the author of many scientific research articles and books including First spectra of neon, argon, and xenon 136 in the 1.2-4.0 µm region, written in 1973 while he was at Purdue University, Lafayette, Indiana.

Other works include:

• T.L.De Bruin, C.J.Humphreys, and W.F.Meggers, J. Res. NBS (U.S.) 11, 409 (1933).
• "The 29 and 30 electron-system spectra of arsenic and selenium" Curtis J Humphreys, 1928.
• "Element Ne I" Meggers, W. F., and Humphreys, C. J. 1933, J. Res. N. B. S. 10, 427. [EA, 7724-18549, a UMT and RMTsource] C.J.Humphreys, J. Res. NBS (U.S.) 22, 19 (1939). C.J.Humphreys, J. Opt. Soc. Am. 43, 1027 (1953).
• "Humphreys Series" Humphreys, C.J., J. Research Natl. Bur. Standards 1953, 50, 1.
• "Interferometric measurement of wavelengths of infrared atomic emission lines in the extraphotographic region" Applied Optics, 1963. Co-authored Rao, K. Narahari;
• Curtis J. Humphreys; D.H. Rank, "Wavelength Standards in the Infrared" ,Academic Press, 1966.
• Humphreys, C. J., & Paul, E. 1970, J. Opt. Soc. Am., 60, 1302.
• H.H. Li and C.J. Humphreys and J. Opt. Soc. Am. 64 (1974) 1072.
• C.J. Humphreys, Rep. Prog. Phys. 42 (1979) 122.